Ebola virus and Marburg virus are related viruses that cause hemorrhagic fevers — illnesses marked by severe bleeding (hemorrhage), organ failure and, in many cases, death. Both viruses are native to Africa, where sporadic outbreaks have occurred for decades.

Ebola virus and Marburg virus live in animal hosts, and humans can contract the viruses from infected animals. After the initial transmission, the viruses can spread from person to person through contact with body fluids or contaminated needles.

No drug has been approved to treat either virus. People diagnosed with Ebola or Marburg virus receive supportive care and treatment for complications. Scientists are coming closer to developing vaccines for these deadly diseases.

The Centers for Disease Control and Prevention monitors the United States for conditions such as Ebola infection, and its labs can test for the Ebola virus. Mayo Clinic does not test for the Ebola and Marburg viruses.

Signs and symptoms typically begin abruptly within five to 10 days of infection with Ebola or Marburg virus. Early signs and symptoms include:

Fever

Severe headache

Joint and muscle aches

Chills

Weakness

Over time, symptoms become increasingly severe and may include:

Nausea and vomiting

Diarrhea (may be bloody)

Red eyes

Raised rash

Chest pain and cough

Stomach pain

Severe weight loss

Bleeding, usually from the eyes, and bruising (people near death may bleed from other orifices, such as ears, nose and rectum)

Internal bleeding

Ebola virus has been found in African monkeys, chimps and other nonhuman primates. A milder strain of Ebola has been discovered in monkeys and pigs in the Philippines. Marburg virus has been found in monkeys, chimps and fruit bats in Africa.

Transmission from animals to humans

Experts suspect that both viruses are transmitted to humans through an infected animal's bodily fluids. Examples include:

Blood. Butchering or eating infected animals can spread the viruses. Scientists who have operated on infected animals as part of their research have also contracted the virus.

Waste products. Tourists in certain African caves and some underground mine workers have been infected with the Marburg virus, possibly through contact with the feces or urine of infected bats.

Transmission from person to person

Infected people typically don't become contagious until they develop symptoms. Family members are often infected as they care for sick relatives or prepare the dead for burial.

Medical personnel can be infected if they don't use protective gear, such as surgical masks and gloves. Medical centers in Africa are often so poor that they must reuse needles and syringes. Some of the worst Ebola epidemics have occurred because contaminated injection equipment wasn't sterilized between uses.

There's no evidence that Ebola virus or Marburg virus can be spread via insect bites.

For most people, the risk of getting Ebola or Marburg viruses (hemorrhagic fevers) is low. The risk increases if you:

Travel to Africa. You're at increased risk if you visit or work in areas where Ebola virus or Marburg virus outbreaks have occurred.

Conduct animal research. People are more likely to contract the Ebola or Marburg virus if they conduct animal research with monkeys imported from Africa or the Philippines.

Provide medical or personal care. Family members are often infected as they care for sick relatives. Medical personnel also can be infected if they don't use protective gear, such as surgical masks and gloves.

Prepare people for burial. The bodies of people who have died of Ebola or Marburg hemorrhagic fever are still contagious. Helping prepare these bodies for burial can increase your risk of developing the disease.

Both Ebola and Marburg hemorrhagic fevers lead to death for a high percentage of people who are affected. As the illness progresses, it can cause:

Multiple organ failure

Severe bleeding

Jaundice

Delirium

Seizures

Coma

Shock

One reason the viruses are so deadly is that they interfere with the immune system's ability to mount a defense. But scientists don't understand why some people recover from Ebola and Marburg and others don't.

For people who survive, recovery is slow. It may take months to regain weight and strength, and the viruses remain in the body for weeks. People may experience:

Hair loss

Sensory changes

Liver inflammation (hepatitis)

Weakness

Fatigue

Headaches

Eye inflammation

Testicular inflammation

The possibility of contracting Ebola or Marburg virus is extremely low unless you've had direct contact with the body fluids of an infected person or animal.

If you think that you or a family member may have been exposed to one of the viruses, call your doctor or go to the nearest emergency room immediately. If you're not referred to an infectious disease specialist, ask to see one.

If you're from the United States and traveling or working abroad, the nearest U.S. Embassy can help you find a doctor. If you're from another country, contact your country's embassy. Be sure to tell your doctor or hospital about your symptoms before your visit so that precautions can be taken to prevent transmission of the virus to others.

What you can do

Before your appointment, to help your doctor find the cause of your symptoms, write a list that answers the following questions:

What symptoms do you have? When did they start?

Have you recently traveled in Africa? If so, what part?

If you were recently in Africa, did you hunt or eat monkeys?

Did you recently visit caves or underground mines in Africa?

Are you employed in a lab that uses monkeys from Africa or the Philippines in research?

If possible, take a family member or friend with you. Sometimes it can be difficult to remember all the information provided to you in the hospital or during an appointment. Someone who accompanies you may remember something you missed or forgot.

Ebola and Marburg hemorrhagic fevers are difficult to diagnose because early signs and symptoms resemble those of other diseases, such as typhoid and malaria. If doctors suspect you have Ebola or Marburg viruses, they use blood tests to quickly identify the virus, including:

Enzyme-linked immunosorbent assay (ELISA)

Reverse transcriptase polymerase chain reaction (PCR)

The Centers for Disease Control and Prevention monitors the United States for conditions such as Ebola infection, and its labs can test for the Ebola virus. Mayo Clinic does not test for the Ebola and Marburg viruses.

No antiviral medications have proved effective in treating infection with either virus. Supportive hospital care includes:

Providing fluids

Maintaining blood pressure

Providing oxygen as needed

Replacing lost blood

Treating other infections that develop

Prevention focuses on avoiding contact with the viruses. The following precautions can help prevent infection and spread of Ebola and Marburg.

Avoid areas of known outbreaks. Before traveling to Africa, find out about current epidemics by checking the Centers for Disease Control and Prevention website.

Wash your hands frequently. As with other infectious diseases, one of the most important preventive measures is frequent hand-washing. Use soap and water, or use alcohol-based hand rubs containing at least 60 percent alcohol when soap and water aren't available.

Avoid bush meat. In developing countries, avoid buying or eating the wild animals, including nonhuman primates, sold in local markets.

Avoid contact with infected people. In particular, caregivers should avoid contact with the person's body fluids and tissues, including blood, semen, vaginal secretions and saliva. People with Ebola or Marburg are most contagious in the later stages of the disease.

Follow infection-control procedures. If you're a health care worker, wear protective clothing, such as gloves, masks, gowns and eye shields. Keep infected people isolated from others. Dispose of needles and sterilize other instruments.

Don't handle remains. The bodies of people who have died of Ebola or Marburg disease are still contagious. Specially organized and trained teams should bury the remains, using appropriate safety equipment.

Vaccine development

Scientists are working on a variety of vaccines that would protect people from Ebola or Marburg viruses. Some of the results have been promising, but further testing is needed.

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